Yamato Kazuki, Tanaka Yusuke, Oku Hiromasa, Yasutomi Keita, Kawahito Shoji
Opt Express. 2020 Jun 22;28(13):19152-19162. doi: 10.1364/OE.394760.
In this paper, a quasi-simultaneous multi-focus imaging technique named simulfocus imaging is reported. This technique was developed for measuring an entire object distributed in the depth direction beyond the depth of field (DOF) with high resolution in a single shot. Simulfocus imaging can acquire multiple focal planes in one shot by synchronizing a tunable acoustic gradient index (TAG) lens and a lock-in pixel image sensor. The TAG lens is a tunable-focus lens whose focal position can be changed at a high speed of several tens to several hundreds of kilohertz. The lock-in pixel image sensor is a special image sensor that can execute multiple exposures at an arbitrary timing during a single shooting. The sensor includes a number of photoelectron storage units in each pixel, and the units where the photoelectrons generated by each exposure are stored can be freely selected. Since an image can be acquired for a single storage unit, and the lock-in pixel image sensor has a number of storage units, the lock-in pixel image sensor can acquire multiple images in one shot. By assigning a specific exposure timing to each unit and synchronizing the exposure timing with the focus fluctuation of the TAG lens, it is possible to simultaneously acquire images in different focal planes. To evaluate the system, we conducted experiments to show the effectiveness of simulfocus imaging in microscope and telescope configurations. From the experimental results, it was confirmed that simulfocus was effective in both configurations.
本文报道了一种名为同步聚焦成像的准同时多聚焦成像技术。该技术旨在单次拍摄中以高分辨率测量分布在景深（DOF）之外深度方向上的整个物体。同步聚焦成像通过同步可调谐声梯度折射率（TAG）透镜和锁相像素图像传感器，能够在单次拍摄中获取多个焦平面。TAG透镜是一种可调焦透镜，其焦点位置可以在几十到几百千赫兹的高速下改变。锁相像素图像传感器是一种特殊的图像传感器，它可以在单次拍摄期间的任意时刻执行多次曝光。该传感器在每个像素中包括多个光电子存储单元，并且可以自由选择存储每次曝光产生的光电子的单元。由于可以为单个存储单元获取图像，并且锁相像素图像传感器有多个存储单元，因此锁相像素图像传感器可以在单次拍摄中获取多个图像。通过为每个单元分配特定的曝光时间，并使曝光时间与TAG透镜的焦点波动同步，可以同时获取不同焦平面的图像。为了评估该系统，我们进行了实验，以展示同步聚焦成像在显微镜和望远镜配置中的有效性。从实验结果可以确认，同步聚焦在两种配置中都是有效的。
